<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style>
#div1 {width:200px; height:200px; background:red; filter:alpha(opacity:30);
opacity:0.3;}
</style>
<script>
window.onload=function()
{
	var oDiv=document.getElementById('div1');
	oDiv,onmouseover=function()
	{
		startMove(100);
	};
	oDiv,onmouseout=function()
	{
		startMove(30);
	};
};
var alpha=30;
var timer=null;
function startMove(iTarget)
{
	var oDiv=document.getElementById('div1');
	clearInterval(timer);
	timer=setInterval(function(){
		var speed=0;
		if(alpha<iTarget)
		{
			speed=10;
		}
		else
		{
			speed=-10;
		}
		
		if(alpha==iTarget)
		{
			clearInterval(timer);
		}
		else
		{
			alpha+=speed;
			oDiv.style.filter='alpha(opacity:'+alpha+')';
			oDiv.style.opacity=alpha/100;
		}
		},30);
}
</script>
</head>

<body>
<div id="div1">
</div>
</body>
</html>
